Photoelectric conversion apparatus and manufacturing method of same

ABSTRACT

An image reading apparatus ( 10 ) includes a photoelectric conversion element formation substrate ( 4 ) having a plurality of photoelectric conversion elements ( 2 ) on a reverse surface of an information reading surface, and a supporting substrate ( 1 ) bonded by an adhesive resin ( 5 ) to the photoelectric conversion element formation substrate ( 4 ) so that the supporting substrate ( 1 ) is integrated with the photoelectric conversion element formation substrate ( 4 ) and faces the plurality of photoelectric conversion elements ( 2 ) on the photoelectric conversion element formation substrate ( 4 ). With this arrangement, provided is a photoelectric conversion apparatus and manufacturing method of same in which (a) a process of bonding a micro glass sheet is not required and (b) a protrusion of an installation portion toward a surface of a document is eliminated.

TECHNICAL FIELD

The present invention relates to a photoelectric conversion apparatuscapable of reading information of documents, photographs, business cardsand the like, and relates to a manufacturing method of same.

BACKGROUND ART

There has been conventionally known image sensors that areclose-touching-type photoelectric conversion apparatuses in which largenumbers of photoelectric conversion means (e.g. photodiodes,phototransistors) and switching elements (e.g. thin film transistors)are disposed in a line or two dimensionally in lines.

Examples of such image sensors are active-matrix-type image readingapparatuses disclosed in Japanese Publication for unexamined Utilitymodel, No. 2-8055/1990 (Jitsukaihei; publication date: Jan. 18, 1990)and in Japanese Publication for Unexamined Patent Application, No.5-243547/1993 (Tokukaihei; publication date: Sep. 21, 1993).

As shown in FIG. 14, in the active-matrix-type image reading apparatus,each pixel 81 of active matrix array, in which pixels are arrayed in anX-Y matrix, has an optical-sensor-use TFT (Thin Film Transistor) 82 anda switching-use TFT 83. The optical-sensor-use TFT 82 is a photoelectricconversion element, and the switching-use TFT 83 is a switching element.The optical-sensor-use TFT 82 of each pixel 81 is so designed thatelectric properties thereof are changed in accordance with whether aphotogenic subject, such as a surface of a document, is white or black(bright or dark).

Specifically, because a resistance value of a phototransistor, which isused as the optical-sensor-use TFT 82, is changed in accordance withbrightness (bright or dark) of light, an amount of electrical charge inan image capacitor (charge capacitor) connected to the phototransistor,or a voltage applied to each pixel 81 is changed. Therefore,two-dimensional information of the photogenic subject can be obtained bysequentially reading out an electrical charge distribution or a voltagedistribution of the image capacitor by using the switching-use TFT 83.

For example, as disclosed in Japanese Publication for Unexamined PatentApplication, No. 6-350070/1994 (Tokukaihei; publication date: Dec. 22,1994), in a close-touching-type photoelectric conversion apparatus, itis necessary, regardless of whether a close-touching-type photoelectricconversion apparatus is one-dimensional line-sensor-use photoelectricconversion apparatus or two-dimensional area-sensor-use photoelectricconversion apparatus, to form a transparent protective layer overphotoelectric conversion means, such as thin film phototransistors,photodiodes, or photoconductors, after the photoelectric conversionmeans is formed on a substrate.

The protective layer is provided for protecting the photoelectricconversion means including semiconductor elements.

Specifically, as shown in FIG. 15, a photoelectric conversion elementformation substrate 92, on which photoelectric conversion elements 91are provided, and a protective layer 93 made of a thin glass substrate,such as a micro glass sheet, are bonded together by using an adhesiveresin 94.

In this case, a light source 95, which functions as a backlight, ispositioned under the photoelectric conversion element formationsubstrate 92, on which the photoelectric conversion elements 91 areprovided. A document to be read is placed on the protective layer 93.Light emitted from the light source 95 passes through an opening section(transparent section) of the photoelectric conversion apparatus, and isradiated onto the document. The light radiated onto the document isreflected by a surface of the document, and enters into thephotoelectric conversion elements 91.

However, the conventional photoelectric conversion apparatuses andmanufacturing methods of same have the following problems.

(1) In a case where a high-definition photoelectric conversion apparatusis needed, a thickness of the protective layer (micro glass sheet) mustbe reduced. For example, in a case of a photoelectric conversionapparatus having a pixel density of 300 dpi, a pixel pitch isapproximately 85 μm. In this case, it is necessary to set the thicknessof the protective layer to approximately 50 μm, which is thinner thanthe pixel pitch. Otherwise, inter-pixel crosstalk of the light reflectedby the document becomes so significant as to blur an image. In a casewhere the pixel density is 500 dpi, the pixel pitch is approximately 50μm. In this case, the thickness of the protective layer must be reducedfurther, to approximately 30 μm.

If the thin protective layer is made of micro glass sheet, as inconventional arrangements, it is difficult to evenly bond the protectivelayer, by using the adhesive resin, to the substrate on which thephotoelectric conversion elements have been formed. This is because themicro glass sheet is difficult to handle due to fragileness, and caneasily be distorted. Therefore, such an arrangement and manufacturingmethod of the photoelectric conversion apparatus are needed that do notrequire a process of bonding the micro glass sheet.

(2) To the substrate on which the photoelectric conversion elements areprovided, also provided are large numbers of switching elements and thelike disposed in matrix or in a line. Therefore, it is necessary toinstall, in a peripheral portion (edge portion) of the substrate, adriving LSI (Large Scale Integrated Circuit) for driving the switchingelements, a reading LSI for reading electric information obtained fromthe photoelectric conversion elements, and/or a flexible printed circuit(FPC), for example.

In installing the LSIs in the peripheral portion of the substrate, a COG(Chip On Glass) method or a TCP (Tape Carrier Package) method isemployed, for example. In the COG method, an LSI chip is directlyinstalled on a substrate. In the TCP method, an LSI is installed to atape, and the tape is installed on a substrate. In a case where the LSIsare installed by the COG method or the TCP method, or in a case wherethe FPC (Flexible Printed Circuit) is installed, it is necessary toprovide a cover for protecting an installation portion, that is, theportion where the LSIs are installed. As a result, the installationportion in the peripheral portion of the substrate inevitably protrudestoward a surface of the document as compared with the protective layerprovided to an image-pickup region.

In a case where close-touching-type photoelectric conversion elementsare used, it is necessary to cause the document-to be in close contactwith the protective layer, so as to read the image. If the document hasa large size, however, the document is hindered from closely touchingthe protective layer because of the protrusion of the installationportion. This causes problems of distortion and blur in an input image.Therefore, such an arrangement and manufacturing method of thephotoelectric conversion apparatus are needed in which the installationportion of the LSIs and the FPC on a document-image-pickup plane, thatis, on a surface on which the protective layer is provided, iseliminated.

The present invention is made in light of the problems above. An objectof the present invention is to provide a photoelectric conversionapparatus and manufacturing method of same in which (a) the process ofbonding the micro glass sheet is not required and (b) the protrusion ofthe installation portion toward the surface of the document iseliminated.

DISCLOSURE OF INVENTION

To solve the problems above, the present invention provides a displayapparatus including: a photoelectric conversion element formationsubstrate having, on a photoelectric conversion element formationsurface thereof, a plurality of photoelectric conversion elements, thephotoelectric conversion element formation surface being a reversesurface of an information reading surface; and a supporting substratebonded by an adhesive material to the photoelectric conversion elementformation substrate so that the supporting substrate is integrated withthe photoelectric conversion element formation substrate and faces theplurality of photoelectric conversion elements on the photoelectricconversion element formation substrate.

In this invention, the photoelectric conversion element formationsubstrate has the plurality of photoelectric conversion elements formedthereon, and the supporting substrate is bonded by the adhesive materialto the photoelectric conversion element formation substrate so that thesupporting substrate is integrated with the photoelectric conversionelement formation substrate and faces the plurality of photoelectricconversion elements on the photoelectric conversion element formationsubstrate.

In this arrangement, therefore, the information reading surface is areverse surface of the photoelectric conversion element formationsurface, and the photoelectric conversion element formation substratealso functions as a protective substrate for protecting thephotoelectric conversion elements from touching the document.

By adopting this arrangement, it is no longer necessary to additionallyprovide a micro glass sheet, which has a protective effect, and to bondthe micro glass sheet to the photoelectric conversion element formationsubstrate, unlike in the conventional arrangements.

As a result, it is possible to provide a photoelectric conversionapparatus that does not require the process of bonding the micro glasssheet as a protective substrate.

Moreover, in the photoelectric conversion apparatus of the presentinvention having the same arrangement, the supporting substrate isthicker than the photoelectric conversion element formation substrate.

With this arrangement, it is possible to structurally reinforce thephotoelectric conversion element formation substrate by the supportingsubstrate, even if the photoelectric conversion element formationsubstrate is thin.

Moreover, the photoelectric conversion apparatus of the presentinvention further includes: a display medium between the photoelectricconversion element formation substrate and the supporting substrate; andan active element on the photoelectric conversion element formationsurface, for driving the display medium.

In this arrangement, the display medium is provided between thephotoelectric conversion element formation substrate and the supportingsubstrate, and the display medium is driven by the active element. As aresult, it is possible to realize a photoelectric conversion apparatuscapable of reading (inputting) and displaying (outputting) an imageby-using a single screen.

To solve the problems above, the present invention provides amanufacturing method of a photoelectric conversion apparatus for readinginformation, including the steps of: installing, on a reverse surface ofan information reading surface of a first substrate, (a) a plurality ofphotoelectric conversion elements and (b) a semiconductor integratedcircuit (IC: Integrated Circuit), which is necessary for driving theplurality of photoelectric conversion elements; bonding a secondsubstrate by an adhesive material to the first substrate so that thesecond substrate covers the plurality of photoelectric conversionelements on the reverse surface of the information reading surface; andprocessing the information reading surface of the first substrate byetching or grinding so as to reduce a thickness of the first substrate.

In this invention, first, in the step of installing, installed on thereverse surface of the information reading surface of the firstsubstrate are (a) the plurality of photoelectric conversion elements and(b) the semiconductor integrated circuit (IC), which is necessary fordriving the plurality of photoelectric conversion elements. Next, in thesteps of bonding, the second substrate is bonded by the adhesivematerial to the first substrate so that the second substrate covers theplurality of photoelectric conversion elements on the reverse surface ofthe information reading surface. Thereafter, in the step of processing,the information reading surface of the first substrate is processed byetching or grinding so as to reduce the thickness of the firstsubstrate.

With this arrangement, the step of bonding a micro glass sheet as aprotective substrate, which is conventionally required, is no longernecessary. As a result, it is easy to manufacture the photoelectricconversion apparatus.

Conventionally, a thin micro glass sheet is bonded as a protectivesubstrate. Therefore, one problem in handling the thin micro glass sheetis that the thin micro glass sheet is often damaged.

In contrast, in the present invention, the reverse surface of thephotoelectric conversion element formation surface is ground after thephotoelectric conversion elements are formed on the photoelectricconversion element formation surface, instead of bonding the micro glasssheet as a protective substrate. In this way, a problem of damage to theprotective substrate is avoided. As a result, it is possible to preventa yield of products from being lowered.

Therefore, it is possible to provide a manufacturing method of aphotoelectric conversion apparatus that does not require the process ofbonding the micro glass sheet and that is capable of preventing theyield of products from being lowered.

Moreover, in the present invention, not only the plurality ofphotoelectric conversion elements, but also the semiconductor integratedcircuit (IC), which is necessary for driving the photoelectricconversion elements, is installed in the step of installing. Therefore,the semiconductor integrated circuit (IC) is formed on the reversesurface of the information reading surface. As a result, the informationreading surface is a flat and smooth surface of the photoelectricconversion element formation substrate, and the protrusion of theinstallation portion of the semiconductor integrated circuit (IC), theTCP, and/or the FPC, for example, which has conventionally existed, iseliminated.

As a result, it is possible to provide a manufacturing method of aphotoelectric conversion apparatus in which the protrusion of theinstallation portion toward the surface of the document is eliminated.

To attain the object above, the present invention provides amanufacturing method of a photoelectric conversion apparatus for readinginformation, including the steps of: installing, on a reverse surface ofan information reading surface of a first substrate, (a) a plurality ofphotoelectric conversion elements and (b) a TCP (Tape Carrier Package)and/or an FPC (Flexible Printed Circuit), which is necessary for drivingthe plurality of photoelectric conversion elements; bonding a secondsubstrate by an adhesive material to the first substrate so that thesecond substrate covers the plurality of photoelectric conversionelements on the reverse surface of the information reading surface; andprocessing the information reading surface of the first substrate byetching or grinding so as to reduce a thickness of the first substrate.

With this invention, it is possible to provide a manufacturing method ofa photoelectric conversion apparatus that does not require the processof bonding the micro glass sheet and that is capable of preventing theyield of products from being lowered.

In the present invention, not only the plurality of photoelectricconversion elements, but also the TCP and/or the FPC, which is necessaryfor driving the plurality of photoelectric conversion elements, isinstalled in the step of installing on the reverse surface of theinformation reading surface of the first substrate.

Therefore, the TCP and/or the FPC is formed on the reverse surface ofthe information reading surface. As a result, the information readingsurface is a flat and smooth surface of the photoelectric conversionelement formation substrate, and the protrusion of the installationportion of the TCP, and/or the FPC, for example, which hasconventionally existed, is eliminated.

As a result, it is possible to provide a manufacturing method of aphotoelectric conversion apparatus in which the protrusion of theinstallation portion toward the surface of the document is eliminated.

For a fuller understanding of the nature and advantages of theinvention, reference should be made to the ensuing detailed descriptiontaken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view illustrating an image reading apparatusin one embodiment of the present invention.

FIG. 2(a) is a cross-sectional view illustrating a step of forming arrayof switching elements and photoelectric conversion elements on a glasssubstrate (first substrate) in the image reading apparatus. FIG. 2(b) isa cross-sectional view illustrating a step of bonding a facingsupporting substrate (second substrate) by an adhesive agent. FIG. 2(c)is a cross-sectional view illustrating a step of etching back the glasssubstrate (first substrate) so as to produce the glass substrate into amicro glass sheet protective film. FIG. 2(d) is a cross-sectional viewillustrating where a light source is installed so as to read a document.

FIG. 3 is a cross-sectional view illustrating how the photoelectricconversion elements are provided to the first substrate.

FIG. 4 is a cross-sectional view illustrating the photoelectricconversion elements including TFTs of a top gate structure.

FIG. 5 is a cross-sectional view illustrating an image reading apparatusin another embodiment of the present invention.

FIG. 6(a) is a cross-sectional view of the image reading apparatus,illustrating a step of forming array of switching elements andphotoelectric conversion elements on a glass substrate (firstsubstrate), and installing an IC in a peripheral portion of thesubstrate. FIG. 6(b) is a cross-sectional view illustrating a step ofbonding a facing supporting substrate (second substrate) by an adhesiveagent. FIG. 6(c) is a cross-sectional view illustrating a step ofetching back the glass substrate (first substrate) so as to produce theglass substrate into a micro glass sheet protective film. FIG. 6(d) is across-sectional view illustrating a step of installing a light source.

Showing an image reading apparatus in yet another embodiment of thepresent invention, FIG. 7(a) is a cross-sectional view in illustrating astep of forming array of switching elements and photoelectric conversionelements on a glass substrate (first substrate) and installing an FPC ora TCP in a peripheral portion of the substrate. FIG. 7(b) is across-sectional view illustrating a step of bonding a facing supportingsubstrate (second substrate) by an adhesive agent. FIG. 7(c) is across-sectional view illustrating a step of etching back the glasssubstrate (first substrate) so as to produce the glass substrate into amicro glass sheet protective film. FIG. 7(d) is a cross-sectional viewillustrating a step of installing a light source, and illustrating afinished product.

Showing the image reading apparatus in yet another embodiment of thepresent invention, FIG. 8 is a plan view illustrating such an imagereading apparatus in which a single TFT functions as (a) aphototransistor as a photoelectric conversion element and (b) atransistor as a switching element.

FIG. 9 shows the image reading apparatus in yet another embodiment ofthe present invention by a cross-sectional view illustrating anarrangement of the image reading apparatus for use as an image-pickupapparatus that deals with X-rays by an indirect conversion method.

FIG. 10 shows an image reading apparatus in a further embodiment of thepresent invention by a cross-sectional view illustrating an arrangementof an image reading apparatus having a function of displaying by liquidcrystal.

FIG. 11 shows an arrangement of a modification example of the imagereading apparatus by a cross-sectional view illustrating an arrangementof an image reading apparatus in which a color filter (CF) substrate isprovided in addition to a second substrate.

FIG. 12 shows an arrangement of another modification example of theimage reading apparatus by a cross-sectional view illustrating anarrangement of an image reading apparatus employing a display mode thatdoes not require a polarizer.

FIG. 13 shows an image reading apparatus in another further embodimentof the present invention by a cross-sectional view illustrating anarrangement of an image reading apparatus having a displaying functionby using an EL element.

FIG. 14 is a plan view illustrating an arrangement of a conventionalimage reading apparatus.

FIG. 15 is a cross-sectional view illustrating, the arrangement of theconventional image reading apparatus.

BEST MODE FOR CARRYING OUT THE INVENTION

The following embodiments and comparative examples provide more detaileddescriptions of the present invention. It should be noted, however, thatthe present invention is not limited by the descriptions below.

Embodiment 1

One embodiment of the present invention is described below withreference to FIGS. 1 to 4.

As shown in FIG. 1, an image reading apparatus 10, which is aphotoelectric conversion apparatus of the present embodiment, is soarranged that a supporting substrate 1 is bonded by an adhesive resin 5,which is an adhesive material, to a photoelectric conversion elementformation substrate 4 on which photoelectric conversion elements 2 andswitching elements 3 are formed. A characteristic of the image readingapparatus 10 is that the photoelectric conversion element formationsubstrate 4 is thinner than the supporting substrate 1.

Specifically, the photoelectric conversion element formation substrate 4is a substrate of approximately 50 μm in thickness, while the supportingsubstrate 1 is a substrate of approximately 0.5 to 2 mm in thickness.This makes it possible to use the photoelectric conversion elementformation substrate 4 as a protective substrate for protecting a surfacethat touches a document. Thus, the photoelectric conversion elementformation substrate 4 is used as a protective substrate, instead of amicro glass sheet used in the conventional photoelectric conversionapparatus shown in FIG. 11. To a side associated with a light source 6,which is a backlight, provided is the supporting substrate 1 forsupporting the thin photoelectric conversion element formation substrate4. Note that pixel array may be disposed one-dimensionally ortwo-dimensionally.

A process of forming the image reading apparatus 10 of the abovearrangement is described below with reference to FIGS. 2(a) to 2(d).

As shown in FIG. 2(a), first, as usual, the pixel array including thephotoelectric conversion elements 2 are formed on a first substrate 21that is made, for example, of a glass substrate of 0.7 mm in thickness.Each pixel includes (a) the switching element 3, such as a TFT connectedto the photoelectric conversion element 2, and (b) a storage capacitor(not shown), in addition to the photoelectric conversion element 2, suchas a photodiode, a phototransistor, or a photoconductor, for example. Itis preferable that, in a case where visible light is to be received, anamorphous silicon film is used in the photoelectric conversion element 2as a semiconductor film, that is, as a photoconduction film. It is alsopreferable that the switching elements 3 are TFTs made of amorphoussilicon or polysilicon.

Note that, in order to detect light entering from a reverse surface ofthe first substrate 21, that is, a reverse surface of a surface on whichthe photoelectric conversion elements 2 are formed, it is necessary tooptimize an arrangement, that is, a direction, of the photoelectricconversion elements 2, as shown in FIG. 3. Specifically, in a case wherethe photoelectric conversion elements 2 are a multilayer-type diode inwhich a semiconductor layer 24 is sandwiched between a transparentelectrode 22 and a metal electrode 23, for example, it is necessary toso design the diode that the transparent electrode 22 becomes a lowerlayer and the metal electrode 23 becomes an-upper layer on the firstsubstrate 21, thereby enabling the light entering from the reversesurface of the first substrate 21 to enter into the semiconductor layer24 via the transparent electrode 22.

In a case where the photoelectric conversion elements 2 arephototransistors (light-detecting TFTs), it is necessary to formtop-gate-structured TFTs so that a gate electrode 26 does not hinder,from entering into the semiconductor layer 24 (channel region of theTFTs), the light entered from the reverse surface of the first substrate21, as shown in FIG. 4. Here, the top-gate-structured TFTs are TFTs inwhich the gate electrode 26 is provided above a channel layer 27 (a-Sior poly-Si).

It is preferable that the photoelectric conversion elements 2 and theswitching elements 3 are covered with a passivation film made of asilicon nitride film.

Next, as shown in FIG. 2(b), a second substrate 31 made of, for example,a glass substrate of 0.7 mm in thickness which functions as thesupporting substrate 1 is prepared, and is bonded by using the adhesiveresin 5 to a surface on which the photoelectric conversion elements 2are provided. At this stage, the photoelectric conversion elements 2 andthe switching elements 3 are completely sealed against outside air.Although various materials may be used as the adhesive resin 5, such asan epoxy resin, an acrylic resin, or a silicone resin, a transparentresin material should be used because it is necessary to allow the lightfrom the light source 6 to efficiently pass through the adhesive resin5.

Then, as shown in FIG. 2(c), an outer surface of the first substrate 21is ground, by grinding or etching, to a predetermined thickness.Specifically, the first substrate 21 made of the glass substrate of 0.7mm in thickness is ground to be 100 μm or less in thickness.

For grinding the first substrate 21, methods to be employed aremechanical grinding (physical grinding) or chemical grinding. Examplesof mechanical grinding methods that may be employed here are (i) asandblast method, in which ceramic grinding particles are sprayed, (ii)grinding by a wrapping sheet or a grinding stone, or a CMP (ChemicalMechanical Polishing) method in which abrasive particles and a chemicalsolvent are used in combination.

On the other hand, in a chemical grinding (sometimes called “wetetching”) method that may be used here, a chemical solution is added toa tub, and heated to a predetermined temperature. Then, a glasssubstrate to be ground is soaked in the tub. In this method, if ahydrofluoric-acidic solution is used for processing the glass, forexample, there is a possibility that an uneven pattern having a shortpitch is formed on a surface of the glass, due to reactions betweenhydrofluoric acid and the surface of the glass. In this case, it ispossible to cause the reactions to be as even as possible by adding anadditive to the solvent or by controlling temperatures. By doing so, thethickness of the glass substrate can be reduced evenly.

In the present embodiment, because it is necessary to grind, easily andevenly, a glass substrate having a large area, it is preferable that thechemical grinding method employed is such that batch processing can beeasily performed.

If grinding of the supporting substrate 1 is also performed in thechemical grinding, the supporting substrate 1 becomes thin, andtherefore becomes unable to perform a function of the supportingsubstrate 1. In order to prevent this, it is preferable that a surfaceof the supporting substrate 1 is protected during the step of chemicalgrinding by, for example, a resin sheet that is resistant to a chemicalgrinding solution.

Alternatively, the supporting substrate 1 may be made of a plasticsubstrate, which is resistant to chemical grinding solvents for glass.

Besides the above-mentioned grinding methods, etching methods such as adry etching or an RIE (Reactive lo,n Etching) method may be employed soas to reduce the thickness of the glass. In the dry etching, thesubstrate is set in a vacuum chamber, and glass is resolved by a gasfilled into the chamber. In the RIE method, a force generated bycollision of ions that are accelerated by a bias is utilized incombination with the dry etching.

Next, as shown in FIG. 2(d), in a thus prepared main body of thephotoelectric conversion apparatus, the light source 6 is provided underthe supporting substrate 1, and a document P is placed so as to closelytouch the outer surface of the first substrate 21, that is, thephotoelectric conversion element formation substrate 4. In this way, itbecomes possible to read a document P, as in the conventionalarrangements.

With the photoelectric conversion apparatus and the manufacturing methodof same, unlike in the conventional arrangements, the process of bondingthe very thin micro glass sheet to the photoelectric conversion elementformation substrate is not necessary.

As described above, the process of bonding the micro glass sheet isconventionally required. Here, the micro glass sheet is difficult tohandle because of fragileness, and can easily be distorted. Therefore,it is difficult to evenly bond the micro glass sheet by using theadhesive resin 5 to the substrate on which the photoelectric conversionelements 2 are provided.

In contrast, because the process of bonding the micro glass sheet is notnecessary in the present embodiment, it is possible to improveproductivity and a rate of non-defective products.

As described above, in the image reading apparatus 10 of the presentembodiment, the photoelectric conversion element formation substrate 4has the plurality of photoelectric conversion elements formed thereon,and the supporting substrate 1 is bonded by the adhesive resin 5 to thephotoelectric conversion element formation substrate 4 so that thesupporting substrate 1 and the photoelectric conversion elementformation substrate 4 are integrated, and so that the supporting element1 faces the plurality of photoelectric conversion elements 2 on thephotoelectric conversion element formation substrate 4.

In this arrangement, therefore, the information reading surface is thereverse surface of the photoelectric conversion element formationsurface, and the photoelectric conversion element formation substrate 4also functions as a protective substrate for protecting thephotoelectric conversion elements 2 from a damage by the document P.

By adopting this arrangement, it is no longer necessary to additionallyprovide a micro glass sheet as a protective substrate, and to bond themicro glass sheet to the photoelectric conversion element formationsubstrate 4, as in the conventional arrangements.

As a result, it is possible to provide a photoelectric conversionapparatus 10 that does not require the process of bonding the microglass sheet as a protective substrate.

Moreover, in the photoelectric conversion apparatus 10 of the presentinvention, the second substrate 31 is thicker than the first substrate21. With this arrangement, it is possible to structurally reinforce thefirst substrate 21 by the second substrate 31, even if the firstsubstrate 21 is thin.

Moreover, in the manufacturing method of the image reading apparatus 10of the present embodiment, the first substrate 21 is made of glass. Inthe step of processing, the first substrate 21 is ground by the chemicalgrinding. By using a glass substrate as the first substrate 21, it ispossible to employ the chemical grinding in processing the reversesurface of the first substrate 21 so as to reduce the thickness thereof.In the chemical grinding, the thickness of the glass substrate isreduced by chemical erosion caused by soaking the first substrate 21 inthe solvent. This makes it possible to statically process the firstsubstrate 21. Therefore, damages to products in a course of processingcan be reduced, as compared, for example, with a case where the physicalgrinding is carried out.

As a result, it is possible to provide a manufacturing method of aphotoelectric conversion apparatus that is capable of preventingdecrease in yield of products.

Moreover, in the image reading apparatus 10 of the present invention,the plurality of photoelectric conversion elements 2 include asemiconductor layer, and there is not a metal electrode but atransparent section between the photoelectric conversion elementformation substrate 4 and the semiconductor layer. As a result, readingof the document P is not hindered by the metal electrode 23 or the gateelectrode 26.

Embodiment 2

Another embodiment of the present invention is described below withreference to FIGS. 5 and 6. Note that, for a purpose of easyexplanation, members having the same functions as those of members shownin the figures in EMBODIMENT 1 are labeled with the same referentialnumerals, and explanations thereof are omitted.

As shown in FIG. 5, in an image reading apparatus 40, which is aphotoelectric conversion apparatus of the present embodiment, pixelarray including photoelectric conversion elements 2 and switchingelements 3 are formed on a first substrate 21. Thereafter, an IC 41,which is a semiconductor integrated circuit such as (a) a driving IC(LSI) for driving the photoelectric conversion elements 2 and theswitching elements 3, or (b) a reading IC (LSI) for reading electricsignals from the photoelectric conversion elements 2, is installed in aperipheral portion of the photoelectric conversion element formationsubstrate 4, which is a first substrate 21.

The IC 41 may be electrically connected via an anisotropic conductiveadhesive agent 42 to wiring patterns formed on the photoelectricconversion element formation substrate 4, or may be monolithicallyformed on the photoelectric conversion element formation substrate 4,directly.

Here, a method employed in monolithically forming the IC 41, such as thedriving IC or the reading IC, is a method in which a driving circuit isintegrally formed, when the switching elements 3 are formed, on theperipheral portion of the photoelectric conversion element formationsubstrate 4 by using TFTs that are made of poly-Si whose mobility ishigher than that of a-Si. For more detail, see Shoichi MATSUMOTO ed.,The Liquid Crystal Display Technology: Active Matrix LCD, (Sangyo ToshoKabushiki Kaisha, 1996), particularly Chapter 3 thereof. Otherarrangements are the same as those of EMBODIMENT 1.

A process of forming the image reading apparatus 40 of the abovearrangement is described below, with reference to FIGS. 6(a) to 6(d).Note that, because the process of forming the image reading apparatus 40is substantially the same as the process of forming the image readingapparatus 10 described in EMBODIMENT 1, common steps are described onlyin outline.

As shown in FIG. 6(a), first, pixel array including photoelectricconversion elements 2 are formed on the first substrate 21. Each pixelhas, in addition to the photoelectric conversion element 2, for example,(a) the switching element 3, such as a TFT connected to thephotoelectric conversion element 2, and (b) a storage capacitor (notshown). After that, the IC 41, such as the driving IC or the reading IC,is adhered to the peripheral portion of the first substrate 21 by using,for example, the anisotropic conductive adhesive agent 42.

Next, as shown in FIG. 6(b), a second substrate 31 for functioning as asupporting substrate 1 is bonded to the first substrate 21. Anarrangement and manufacturing method of the bonded first substrate 21and the second substrate 31 are the same as those in FIG. 2(b) ofEMBODIMENT 1. However, at this time, it is preferable that aninstallation portion of the IC 41, such as the driving IC or the readingIC, is simultaneously sealed by using an adhesive resin 5 for connectingthe first substrate 21 and the second substrate 31.

Next, as shown in FIG. 6(c), an outer surface of the first substrate 21is ground, by etching or grinding, to a predetermined thickness. Thisstep of grinding the first substrate 21 to a predetermined thickness byetching or grinding is the same as that of FIG. 2(c) in EMBODIMENT 1.

Then, as shown in FIG. 6(d), in a thus prepared main body of thephotoelectric conversion apparatus, a light source 6 is provided underthe supporting substrate 1, and a document P is caused to closely touchthe outer surface of the first substrate 21, which functions as thephotoelectric conversion element formation substrate 4. In this way, itbecomes possible to read the document P, as in the conventionalarrangements.

In addition to features of the image reading apparatus 10 described inEMBODIMENT 1, the image reading apparatus 40 and a manufacturing methodof same have the following features.

Even if there is the installation portion of IC 41, such as the drivingIC or the reading IC, in the peripheral portion of the image readingapparatus 40, the installation portion is completely molded. Because ofthis, the installation portion is not exposed to or does not protrudetoward the document P. Therefore, it is unnecessary to provide, unlikethe conventional arrangements, a protective cover to the installationportion. This makes it possible to attain a completely flat a surface ofthe image reading apparatus 40 that closely touches the document P. As aresult, even if a size of the document P is larger than an image-pickupsurface of the image reading apparatus 40, the document P closelycontacts a document-reading surface without warping in a vicinity of theIC 41, thereby preventing a phenomenon in which an image read from thedocument P is blurred.

As described above, in the image reading apparatus 40 of the presentembodiment, the IC 41, which is necessary for driving the plurality ofphotoelectric conversion elements 2, is installed on a reverse surfaceof an information reading surface in the peripheral portion of thephotoelectric conversion element formation substrate 4.

Therefore, because the IC 41 is provided on the reverse surface of theinformation reading surface, the information surface is a flat andsmooth surface of the photoelectric conversion element formationsubstrate 4. Thus, unlike in the conventional arrangements, theprotrusion of the installation portion of the IC 41 or the like towardthe surface of the document is eliminated.

As a result, it is possible to provide an image reading apparatus 40that eliminates the protrusion of the installation portion toward thesurface of the document.

In a manufacturing method of the image reading apparatus 40 of thepresent embodiment, first, in a step of installing, the plurality ofphotoelectric conversion elements 2 and the IC 41, which is necessaryfor driving the plurality of photoelectric conversion elements 2, areinstalled on the reverse surface of the information reading surface ofthe first substrate 21. Then, in a step of bonding, the second substrate31 is bonded to the first substrate 21 by using the adhesive resin 5, soas to cover the photoelectric conversion elements 2 and the IC 41, whichare installed on the reverse surface of the information reading surfaceof the first substrate 21. After that, in a step of processing, theinformation reading surface of the first substrate 21 is ground byetching or grinding, so as to reduce a thickness of the first substrate21.

With this arrangement, the process of bonding a micro glass sheet as aprotective substrate, which is conventionally carried out, is no longernecessary. As a result, it is, easy to manufacture the photoelectricconversion apparatus 40.

Conventionally, the thin micro glass sheet is bonded as a protectivesubstrate. Therefore, one problem in handling the thin micro glass sheetis that the thin micro glass sheet is often damaged.

In contrast, in the present embodiment, the reverse surface of thephotoelectric conversion element formation substrate 4 is ground afterthe photoelectric conversion elements 2 are formed on the photoelectricconversion element formation substrate 4, in order to eliminate the stepof bonding the micro glass sheet as a protective substrate. In this way,a damage to the protective substrate is avoided. As a result, it ispossible to prevent a yield of products from being lowered

Therefore, it is possible to provide a manufacturing method of aphotoelectric conversion apparatus 40 that does not require the processof bonding the micro glass sheet and that is capable of preventing theyield of products from being lowered.

Moreover, in the present invention, not only the plurality ofphotoelectric conversion elements 2, but also the IC 41, which isnecessary for driving the photoelectric conversion elements 2, isinstalled in the step of installing. Therefore, the IC 41 is formed onthe reverse surface of the information reading surface. As a result, theinformation reading surface is a flat and smooth surface of thephotoelectric conversion element formation substrate 4, and theprotrusion of the installation portion of the IC 41 or the like towardthe surface of the document, which exists in the conventionalarrangement, is eliminated.

As a result, it is possible to provide a manufacturing method of aphotoelectric conversion apparatus 40 that eliminates the protrusion ofthe installation portion toward the surface of the document.

Embodiment 3

Yet another embodiment of the present invention is described below withreference to FIGS. 7 to 9. Note that, for a purpose of easy explanation,members having the same functions as those of members shown in thefigures in EMBODIMENT 1 and EMBODIMENT 2 are labeled with the samereferential numerals, and explanations thereof are omitted.

In EMBODIMENT 2, the IC 41, such as the driving IC or the reading IC, isinstalled in the peripheral portion of the first substrate 21. However,the present invention is not limited to this arrangement. As shown inFIG. 7(d), the IC41 or the like may be directly installed in theperipheral portion of the first substrate 21 by using a COG method.Alternatively, an image reading apparatus 50 may be such a photoelectricconversion apparatus that adopts a method of externally providing the IC41 or the like by using an FPC or a TCP 51. It should be noted that boththe FPC and the TCP 51 may be provided. Furthermore, such a method maybe employed in which the IC 41, such as the driving IC or the readingIC, is monolithically formed, and only a power source for the IC 41,such as the driving IC or the reading IC, is externally supplied by theFPC.

A process of forming the image reading apparatus 50 of the abovearrangement is described below, with reference to FIGS. 7(a) to 7(d).Note that, because the process of forming the image reading apparatus 50is substantially the same as the process of forming the image readingapparatus 10 described in EMBODIMENT 1 and the image reading apparatus40 described in EMBODIMENT 2, common steps are described only inoutline.

As shown in FIG. 7(a), first, pixel array including photoelectricconversion elements 2 are formed on the first substrate 21. Each pixelincludes, in addition to the photoelectric conversion element 2, forexample, (a) the switching element 3, such as a TFT connected to thephotoelectric conversion element 2, and (b) a storage capacitor (notshown). After that, the FPC or the TCP 51 is adhered to the peripheralportion of the first substrate 21 by using, for example, an anisotropicconductive adhesive agent 52.

Next, as shown in FIG. 7(b), a second substrate 31 for functioning as asupporting substrate 1 is bonded to the first substrate 21. Anarrangement and manufacturing method of the thus bonded first substrate21 and the second substrate 31 are the same as those in FIG. 2(b) ofEMBODIMENT 1 and in FIG. 6(b) of EMBODIMENT 2. At this time, it ispreferable that sealing of an installation portion of the FPC or the TCP51 is also carried out by using an adhesive resin 5 for connecting thefirst substrate 21 and the second substrate 31.

Next, as shown in FIG. 7(c), an outer surface of the first substrate 21is ground, by etching or grinding, to a predetermined thickness. Thisstep of grinding the first substrate 21 to a predetermined thickness byetching or grinding is identical to those of FIG. 2(c) in EMBODIMENT 1and FIG. 6(c) in EMBODIMENT 2. However, at this time, it is preferablethat the FPC or the TCP 51 that protrudes from an edge is molded byusing a resin or the like, so that the FPC or the TCP 51 does not toucha chemical grinding solvent.

Then, as shown in FIG. 7(d), in a thus prepared main body of thephotoelectric conversion apparatus, a light source 6 is provided underthe supporting substrate 1, and a document P is caused to closely touchthe outer surface of the first substrate 21, which functions as thephotoelectric conversion element formation substrate 4. In this way, itbecomes possible to read the document P, as in the conventionalarrangements.

In addition to features of the image reading apparatus 10 described inEMBODIMENT 1 and of the image reading apparatus 40 described inEMBODIMENT 2, the image reading apparatus 50 and a manufacturing methodof same have the following features.

Even if there is the installation portion of the FPC or the TCP 51 inthe peripheral portion of the image reading apparatus 50, theinstallation portion is completely molded. Because of this, theinstallation portion is not exposed to or does not protrude toward thedocument P. Therefore, it is unnecessary to provide, unlike in theconventional arrangements, a protective cover to the installationportion. This makes it possible to attain a completely flat surface ofthe image reading apparatus 50 that closely touches the document P. As aresult, even if a size of the document P is larger than an image-pickupsurface of the image reading apparatus 50, it is possible to prevent aphenomenon in which an image read from the document P is blurred.

As described above, in the image reading apparatus 50 of the presentembodiment, the FPC or the TCP 51, which is necessary for driving theplurality of photoelectric conversion elements 2, is installed in theperipheral portion of the photoelectric conversion element formationsubstrate 4 on a reverse surface of an information reading surface.

Therefore, because the FPC or the TCP 51 is provided on the reversesurface of the information reading surface, the information surface is aflat and smooth surface of the photoelectric conversion elementformation substrate 4. Thus, the protrusion of the installation portionof the FPC or the TCP 51 toward the surface of the document, whichexists in the conventional arrangement, is eliminated.

As a result, it is possible to provide an image reading apparatus 50 inwhich the protrusion of the installation portion toward the surface ofthe document is eliminated.

A manufacturing method of the image reading apparatus 50 of the presentembodiment includes the steps of: installing, on a reverse surface of aninformation reading surface of the first substrate 21, (a) the pluralityof photoelectric conversion elements 2 and (b) the FPC or the TCP 51,which is necessary for driving the plurality of photoelectric conversionelements 2; bonding the second substrate 31 by the adhesive resin 5 tothe first substrate 21 so that the second substrate 31 covers theplurality of photoelectric conversion elements 2 installed on thereverse surface of the information reading surface of the firstsubstrate 21; and processing the information reading surface of thefirst substrate 21 by etching or grinding so as to reduce a thickness ofthe first substrate 21.

Therefore, it is possible to provide a manufacturing method of the imagereading apparatus 50 that does not require the process of bonding amicro glass sheet and that is capable of preventing a yield of productsfrom being lowered.

Moreover, in the present embodiment, not only the plurality ofphotoelectric conversion elements 2, but also the FPC or the TCP 51,which is necessary for driving the photoelectric conversion elements 2,is installed on the reverse surface of the information reading surfacein the step of installing.

Because the FPC or the TCP 51 is formed on the reverse surface of theinformation reading surface, the information reading surface is a flatand smooth surface of the photoelectric conversion element formationsubstrate 4. Thus, the protrusion of the installation portion of the FPCor the TCP 51 toward the surface of the document, which exists in theconventional arrangement, is eliminated.

As a result, it is possible to provide a manufacturing method of aphotoelectric conversion apparatus 50 in which the protrusion of theinstallation portion toward the surface of the document is eliminated.

The invention being thus described, it will be obvious that the same waymay be varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention. For example, inEMBODIMENT 1 to EMBODIMENT 3, the arrangements described are such thateach pixel in the photoelectric conversion apparatuses separatelyincludes the photoelectric conversion element 2 and the switchingelement 3. However, the present invention is not limited to thisarrangement. For example, as shown in FIG. 8, the present invention isapplicable to such a photoelectric conversion apparatus in which asingle TFT performs functions of a phototransistor as the photoelectricconversion element 2 and a transistor as the switching element 2.

Moreover, the photoelectric conversion apparatus of the presentembodiment may be used, for example, as an image-pickup apparatus thatdeals with an X-ray by an indirect conversion method, by forming anX-ray-to-light conversion film (often called scintillator orintensifying screen) on the outer surface of the protective substrate,as shown in FIG. 9.

In this case, it is preferable that the X-ray-to-light conversion filmis made of CsI:T1, Gd2O2S:Tb, or the like. An X-ray that passes througha human body or a test subject is converted into a visible light imageby the X-ray-to-light conversion film. An image of the X-ray can beobtained by receiving the visible light image by the photoelectricconversion apparatus.

Embodiment 4

A further embodiment of the present invention is described below withreference to FIGS. 10 to 12. Note that, for a purpose of easyexplanation, members having the same functions as those of members shownin the figures in EMBODIMENT 1 to EMBODIMENT 3 are labeled with the samereferential numerals, and explanations thereof are omitted.

In EMBODIMENT 1 to EMBODIMENT 3, described are such photoelectricconversion apparatuses and manufacturing methods of the same in which(a) the process of bonding the micro glass sheet as a protectivesubstrate is not required, and (b) the protrusion of the installationportion toward the surface of the document is eliminated. However, thearrangements of the present invention are also applicable to aphotoelectric conversion apparatus having a displaying function. Thefollowing specifically describes a photoelectric conversion apparatushaving a built-in displaying function.

As shown in FIG. 10, an image reading apparatus 60 of the presentembodiment is a photoelectric conversion apparatus having a built-indisplaying function that uses liquid crystal as a displaying medium.

In the image reading apparatus 60, photoelectric conversion elements 2are formed for respective pixels on a first substrate 21, as inEMBODIMENT 1. On a surface on which the photoelectric conversionelements 2 are formed, display-use pixel electrodes 8 for driving adisplay medium (liquid crystal 7, described later) are formed for therespective pixels. Also provided is a switching element 3 as an activeelement for controlling transfer of signal to the photoelectricconversion element 2 and to the display-use pixel electrodes 8. As theswitching element 3, a TFT is suitably used. The TFTs may be providedfor the photoelectric conversion element 2 and for the switching element3 separately, that is, a plurality of TFTs may be provided to eachpixel. Alternatively, a single TFT may be used for driving thephotoelectric conversion element 2 and the switching element 3 perpixel.

On the other hand, on a second substrate 31 as a supporting substrateand as a CF (color filter) substrate, a color filter (CF) 11 and adisplay-use common electrode (such as an ITO) 9 are formed. The firstsubstrate 21 and the second substrate 31 are fixed by adhesion by usinga sealing material, and the liquid crystal 7 is sealed between the firstsubstrate 21 and the second substrate 31.

A backlight, which is a light source 6, functions as a light source forilluminating a photographic object while an image is read, and as abacklight for the liquid crystal display while the image is displayed.

Here, as described in EMBODIMENT 1, it is necessary to reduce thethickness of the first substrate 21 as much as possible, so as toprevent blurring in the image of the photographic object that has beenread. On the other hand, the second substrate 31, which faces the firstsubstrate 21 via a liquid crystal layer, is so designed as to be thickerthan the first substrate, so as to improve mechanical strength of a mainpanel.

As a result, it is possible to enhance the mechanical strength of themain panel, while keeping blurring in the image at minimum. It is ofcourse possible, as in EMBODIMENT 1, to ensure that the photographicobject and an information reading surface are in close contact with eachother, because a portion where electric members (such as an IC, a TCP,and an FPC), which are necessary for driving the photoelectric elements2, are installed does not protrude toward the photographic object.

As in an image reading apparatus 61 shown in FIG. 11, it may be soarranged that (a) a thickness of the first substrate 21 and a thicknessof a color filter (CF) substrate 12 including a color filter (CF) 11that faces the first substrate 21 are simultaneously reduced in theprocess of reducing the thickness of the first substrate 21, (b) thesecond substrate 31 is separately prepared as a supporting substrate,and (c) the second substrate 31 is provided below the color filter (CF)substrate 12.

In this case, a polarization plate 13 may be located between the colorfilter (CF) substrate 12 and the second substrate 31, or may be locatedbelow the second substrate 31, that is, on a side associated with thelight source 6, as shown in FIG. 10.

Usually, if the first substrate 21 and the color filter (CF) substrate12 that are made of the same material (e.g. glass) are bonded togetherand are soaked in a chemical etching solution, not only the firstsubstrate 21, but also the color filter (CF) substrate 12 are usuallyetched to a similar extent, and are simultaneously reduced in thickness.Because of this, it is often difficult to use the color filter (CF)substrate 12 as a supporting substrate. It is therefore preferable thatthe second substrate 31 is additionally prepared so as to have thearrangement of the image reading apparatus 61 shown in FIG. 11.

It may, also be so arranged that a single member functions as the lightsource 6, and the second substrate 31 that plays a role of a supportingsubstrate. In this case, a light guide plate included in the lightsource 6 functions as the supporting substrate.

In a case where a display mode of the liquid crystal 7 requires apolarizer, as in a case of a TN (Twisted Nematic) mode, it is necessaryto insert a polarization plate 14 as a polarizer between the surface onwhich the photoelectric conversion elements 2 are provided and an objectof reading (such as a document P), as shown in FIG. 10. Because a thickpolarization plate 14 aggravates the blurring of the image, it isnecessary that a thickness of the polarization plate 14 be designed asthin as possible.

On the other hand, in a case where a display mode of the liquid crystal7 does not require the polarization plate 14, as in a case of a guesthost mode, it is not necessary to provide the polarization plate 14between the surface on which the photoelectric conversion elements 2 areprovided and the object of reading (such as the document P), as in animage reading apparatus 62 shown in FIG. 12. This is advantageous inthat the blurring of the image is minimized, because a distance betweenthe surface on which the photoelectric conversion elements 2 areprovided and the object of reading (such as the document P) isminimized. Examples of liquid crystal display modes that do not requirea polarizer include, in addition to the guest host (GH) mode, a dynamicscattering (DS) mode, a phase changing (PC) mode, and a polymerdispersed liquid crystal (PDLC) mode.

As described above, the image reading apparatuses 60, 61, and 62 of thepresent embodiment include the liquid crystal 7 between the firstsubstrate 21 and the second substrate 31, and drive the liquid crystal 7using the switching element 3. As a result, each of the image readingapparatuses 60, 61, and 62 is capable of reading (inputting) anddisplaying (outputting) the image by a single screen.

Moreover, in the image reading apparatuses 60, 61, and 62, the liquidcrystal 7 can be sealed between the first substrate 21 and the secondsubstrate 31, and the second substrate 31 can be effectively used as acounter substrate that includes the display-use common electrode 9 fordriving the liquid crystal 7.

Moreover, in the image reading apparatus 62 of the present embodiment,the display mode of the liquid crystal 7 does not require a polarizer.Therefore, it is not necessary to provide the polarization plate 14between the first substrate 21 and the document P. As a result, with theimage reading apparatus 62, the blurring of the image is minimized,because the distance between the photoelectric conversion elements 2 andthe document P is minimized.

Moreover, in the image reading apparatuses 60, 61, and 62, only onelight source 6 is required, by using the light source 6 as a lightsource for illuminating the photographic object while information isread and as a display-use light source while the information isdisplayed. As a result, it is possible to reduce costs for members.

Embodiment 5

Another further embodiment of the present invention is described belowwith reference to FIG. 13. Note that, for a purpose of easy explanation,members having the same functions as those of members shown in thefigures in EMBODIMENT 1 to EMBODIMENT 4 are labeled with the samereferential numerals, and explanations thereof are omitted.

In EMBODIMENT 4, the photoelectric conversion apparatus including theliquid crystal 7 as a display medium is described. However, EL (ElectroLuminescence) elements may be used instead of the liquid crystal 7. Thefollowing specifically describes a photoelectric conversion apparatushaving a function of EL displaying.

As shown in FIG. 13, a photoelectric conversion apparatus 70 of thepresent embodiment is a photoelectric conversion apparatus having abuilt-in display function by using an organic EL as a display medium.

As in EMBODIMENT 1In the photoelectric conversion apparatus 70, aphotoelectric conversion element 2 is formed per pixel on a firstsubstrate 21, which is a photoelectric conversion element formationsubstrate. On a surface on which the photoelectric conversion element 2is formed, an EL element 15 is formed per pixel. Also provided is aswitching element 3 as an active element for controlling transfer ofsignal to the photoelectric conversion element 2 and to the EL element15. As the switching element 3, a TFT is suitably used. The TFTs may beprovided to the photoelectric conversion element 2 and to the EL element15 separately, that is, a plurality of TFTs may be provided to eachpixel. Alternatively, a single TFT may be used for driving thephotoelectric conversion element 2 and the EL element 15.

On the other hand, a second substrate 31, which is a supportingsubstrate, may be used not only to mechanically reinforce the firstsubstrate 21, but also as a layer (film) for shutting off outside airand moisture, which could adversely affect reliability of a barrier filmof an EL layer, that is, the EL element 15. The first substrate 21 andthe second substrate 31 are fixed by adhesion by a molding material 16,which is a sealing material.

Here, as described in EMBODIMENT 1, it is necessary to reduce thethickness of the first substrate 21 as much as possible, so as toprevent blurring in the image of the photographic object that has beenread. On the other hand, the second substrate 31, which is a supportingsubstrate and a barrier substrate that faces the first substrate 31 viaa layer of the EL element 15, is so designed as to be thicker than thefirst substrate, so as to improve mechanical strength of a main panel.

As a result, it is possible to enhance the mechanical strength of themain panel, while keeping the blurring in the image at minimum. It is ofcourse possible, as in EMBODIMENT 1, to ensure that the photographicobject and an information reading surface are in close contact with eachother, because an installation portion of electric members (such as anIC, a TCP, and an FPC), which are necessary for driving thephotoelectric elements 2, does not protrude toward the photographicobject.

As in the image reading apparatus 61 of EMBODIMENT 4 shown in FIG. 11,it may be so arranged that (a) both the first substrate 21 and thebarrier substrate that faces the first substrate 21 are reduced inthickness in the process of reducing a thickness of the first substrate21, (b) the second substrate 31 is separately prepared as a supportingsubstrate, and (c) the second substrate 31 is provided outside of thebarrier substrate.

As described above, the image reading apparatus 70 of the presentembodiment uses the EL element 15 as a display medium. Therefore, it ispossible to perform displaying (outputting) by using the EL element 15.Moreover, because the EL element 15 is sealed between the firstsubstrate 21 and the second substrate 31, it is possible to effectivelyuse the second substrate 31 as a barrier layer for the EL element 15.

Moreover, in the image reading apparatus 70, the EL element 15 is usedas a light source for illuminating the photographic object whileinformation is read, and as a light emitting element while theinformation is read. As a result, it is possible to reduce costs formembers.

It should be noted that the present invention is not limited to theembodiments described above, and may be varied in many ways within thescope of the claims. For example, an embodiment obtained by suitablycombining technical features of one embodiment with those of anotherembodiment should also be regarded as technical features of the presentinvention.

The invention being thus described, it will be obvious that the same waymay be varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

As described, to attain the object above, a display apparatus of thepresent invention includes: a photoelectric conversion element formationsubstrate having, on a photoelectric conversion element formationsurface thereof, a plurality of photoelectric conversion elements, thephotoelectric conversion element formation surface being a reversesurface of an information reading surface; and a supporting substratebonded by an adhesive material to the photoelectric conversion elementformation substrate so that the supporting substrate is integrated withthe photoelectric conversion element formation substrate and faces theplurality of photoelectric conversion elements on the photoelectricconversion element formation substrate.

In this invention, the photoelectric conversion element formationsubstrate has, on the photoelectric conversion element formation surfacethereof, the plurality of photoelectric conversion elements, thephotoelectric conversion element formation surface being the reversesurface of the information reading surface, and the supporting substrateis bonded by the adhesive material to the photoelectric conversionelement formation substrate so that the supporting substrate isintegrated With the photoelectric conversion element formation substrateand faces the plurality of photoelectric conversion elements on thephotoelectric conversion element formation substrate.

With this arrangement, therefore, the information reading surface is thereverse surface of the photoelectric conversion element formationsurface, and the photoelectric conversion element formation substratealso functions as a protective substrate for protecting thephotoelectric conversion elements from touching the document.

Therefore, it is no longer necessary to additionally provide a microglass sheet, which has a protective effect, and bond the micro glasssheet to the photoelectric conversion element formation substrate,unlike the conventional arrangements.

As a result, it is possible to provide a photoelectric conversionapparatus that does not require the process of bonding the micro glasssheet, which is a protective substrate.

Moreover, in the photoelectric conversion apparatus of the presentinvention, the supporting substrate is thicker than the photoelectricconversion element formation substrate.

With this invention, it is possible to structurally reinforce thephotoelectric conversion element formation substrate by the supportingsubstrate, even if the photoelectric conversion element formationsubstrate is thin.

Moreover, in the photoelectric conversion apparatus of the presentinvention, a semiconductor integrated circuit.(IC), which is necessaryfor driving the plurality of photoelectric conversion elements, is in aperipheral portion (edge portion) of the photoelectric conversionelement formation substrate on the photoelectric conversion elementformation surface.

Moreover, in the photoelectric conversion apparatus of the presentinvention, a TCP (Tape Carrier Package) and/or an FPC (flexible printedcircuit), which is necessary for driving the plurality of photoelectricconversion elements, is in a peripheral portion of the photoelectricconversion element formation substrate on the photoelectric conversionelement formation surface.

In this invention, the semiconductor integrated circuit (IC), the TCPand/or the FPC is in the peripheral portion of the photoelectricconversion element formation substrate on the photoelectric conversionelement formation surface. Therefore, the information reading surface isa flat and smooth surface of the photoelectric conversion elementformation substrate, and the protrusion of the installation portion ofthe semiconductor integrated circuit (IC), the TCP, and/or the FPC, forexample, which has conventionally existed, is eliminated.

As a result, it is possible to provide a photoelectric conversionapparatus in which the protrusion of the installation portion toward thesurface of the document is eliminated.

Moreover, the photoelectric conversion apparatus of the presentinvention is a photoelectric conversion apparatus, wherein the pluralityof photoelectric conversion elements include a semiconductor layer, thephotoelectric conversion apparatus further including a transparentsection between the photoelectric conversion element formation substrateand the semiconductor layer.

In this invention, the plurality of photoelectric conversion elementsinclude the semiconductor layer, and the photoelectric conversionapparatus further includes the transparent section between thephotoelectric conversion element formation substrate and thesemiconductor layer. As a result, reading of the document is nothindered by a metal electrode.

Moreover, the photoelectric conversion apparatus of the presentinvention further includes an X-ray-to-light conversion film, on theinformation reading surface of the photoelectric conversion elementformation substrate, for converting an X-ray into light.

In this invention, the photoelectric conversion apparatus furtherincludes the X-ray-to-light conversion film on the information readingsurface of the photoelectric conversion element formation substrate, forconverting an X-ray into light. Therefore, the photoelectric conversionapparatus can be used as an image-pickup apparatus that deals withX-rays by an indirect conversion method.

Moreover, the photoelectric conversion apparatus of the presentinvention further includes: a display medium provided between thephotoelectric conversion element formation substrate and the supportingsubstrate; and an active element on the photoelectric conversion elementformation surface, for driving the display medium.

In this invention, the display medium is provided between thephotoelectric conversion element formation substrate and the supportingsubstrate, and the display medium is driven by the active element. As aresult, it is possible to realize a photoelectric conversion apparatuscapable of reading (inputting) and displaying (outputting) an image byusing a single screen.

Moreover, in the photoelectric conversion apparatus of the presentinvention, the display medium is liquid crystal.

In this invention, it is possible to seal the liquid crystal between thephotoelectric conversion element formation substrate and the supportingsubstrate, and to effectively use the supporting substrate as a countersubstrate that includes a common electrode for driving the liquidcrystal.

Moreover, in the photoelectric conversion apparatus of the presentinvention, a display mode of the liquid crystal, which is the displaymedium, does not require a polarizer. Examples of liquid crystal displaymodes that do not require a polarizer include, in addition to the guesthost (GH) mode, a dynamic scattering (DS) mode, a phase changing (PC)mode, and a polymer dispersed liquid crystal (PDLC) mode, and the like.

In this invention, it is not necessary to install a polarizer betweenthe surface on which the photoelectric conversion elements are providedand an object of reading (such as the document P). As a result, it ispossible to provide a photoelectric conversion apparatus in which theblurring of the image is minimized, because the distance between thephotoelectric conversion elements and the object of reading isminimized.

Moreover, the photoelectric conversion apparatus of the presentinvention further includes a light source provided to one side withrespect to the supporting substrate, while the photoelectric conversionelement formation substrate is provided on the other side (in otherwords, light source provided in such a manner that the light source andthe photoelectric conversion element formation substrate sandwich thesupporting substrate), the light source being used as a light source forilluminating a photographic object while information is read, and as alight source for a liquid crystal display while the information isdisplayed.

With this invention, only one light source is required, by providingsuch a light source that is used as a light source for illuminating thephotographic object while information is read and as a light source fora liquid crystal display while the information is displayed. As aresult, it is possible to reduce costs for members.

Moreover, in the photoelectric conversion apparatus of the presentinvention, the display medium is an EL (Electro Luminescence) element.

With this invention, it is possible to perform displaying (outputting)by using the EL element. Moreover, because the EL element is sealedbetween the photoelectric conversion element formation substrate and thesupporting substrate, it is possible to effectively use the supportingsubstrate as a layer (film) for shutting off outside air and moisture,which could adversely affect reliability of a barrier film of the ELelement, that is, the EL element.

Moreover, in the photoelectric conversion apparatus of the presentinvention, the EL element is used as a light source for illuminating aphotographic object while information is read, and as a light emittingelement while the information is displayed.

In this invention, the EL element is used as a light source forilluminating the photographic object while information is read, and as alight emitting element while the information is displayed. Therefore, itis not necessary to provide another light source. As a result, it ispossible to reduce costs for members.

To solve the problems above, the present invention provides amanufacturing method of a photoelectric conversion apparatus for readinginformation includes the steps of: installing, on a reverse surface ofan information reading surface of a first substrate, (a) a plurality ofphotoelectric conversion elements and (b) a semiconductor integratedcircuit (IC), which is necessary for driving the plurality ofphotoelectric conversion elements; bonding a second substrate by anadhesive material to the first substrate so that the second substratecovers the plurality of photoelectric conversion elements on the reversesurface of the information reading surface; and processing theinformation reading surface of the first substrate by etching orgrinding so as to reduce a thickness of the first substrate.

In this invention, first, in the step of installing, installed on thereverse surface of the information reading surface of the firstsubstrate are (a) the plurality of photoelectric conversion elements and(b) the semiconductor integrated circuit (IC), which is necessary fordriving the plurality of photoelectric conversion elements. Next, in thesteps of bonding, the second substrate is bonded by the adhesivematerial to the first substrate so that the second substrate covers theplurality of photoelectric conversion elements on the reverse surface ofthe information reading surface of the first substrate. Thereafter, inthe step of processing, the information reading surface of the firstsubstrate is processed by etching or grinding so as to reduce thethickness of the first substrate.

With this invention, the step, which is conventionally carried out, ofbonding a micro glass sheet as a protective substrate is no longernecessary. As a result, it is easy to manufacture the photoelectricconversion apparatus.

Conventionally, a thin micro glass sheet is bonded as a protectivesubstrate. Therefore, one problem in handling the thin micro glass sheetis that the thin micro glass sheet is often damaged.

In contrast, in the present invention, the reverse surface of thephotoelectric conversion element formation substrate is ground after thephotoelectric conversion elements are formed, in order to eliminate thestep of bonding the micro glass sheet as a protective substrate. In thisway, a problem of damage to the protective substrate is avoided.Therefore, it is possible to prevent a yield of products from beinglowered.

Therefore, it is possible to provide a manufacturing method of aphotoelectric conversion apparatus that does not require the process ofbonding the micro glass sheet and that is capable of preventing theyield of products from being lowered.

Moreover, in the present invention, not only the plurality ofphotoelectric conversion elements, but also the semiconductor integratedcircuit (IC), which is necessary for driving the photoelectricconversion elements, is installed in the step of installing. Therefore,the semiconductor integrated circuit (IC) is formed on the reversesurface of the information reading surface. As a result, the informationreading surface is a flat and smooth surface of the photoelectricconversion element formation substrate, and the protrusion of theinstallation portion of the semiconductor integrated circuit (IC), theTCP, and/or the FPC, for example, which has conventionally existed, iseliminated.

As a result, it is possible to provide a manufacturing method of aphotoelectric conversion apparatus in which the protrusion of theinstallation portion toward the surface of the document is eliminated.

To solve the problems above, the present invention provides amanufacturing method of a photoelectric conversion apparatus for readinginformation, including the steps of: installing, on a reverse surface ofan information reading surface of a first substrate, (a) a plurality ofphotoelectric conversion elements and (b) a TCP (Tape Carrier Package)and/or an FPC (Flexible Printed Circuit), which is necessary for drivingthe plurality of photoelectric conversion elements; bonding a secondsubstrate by an adhesive material to the first substrate so that thesecond substrate covers the plurality of photoelectric conversionelements on the reverse surface of the information reading surface ofthe first substrate; and processing the information readings surface ofthe first substrate by etching or grinding so as to reduce a thicknessof the first substrate.

With this invention, it is possible to provide a manufacturing method ofa photoelectric conversion apparatus that does not require the processof bonding the micro glass sheet and that is capable of preventing theyield of products from being lowered.

In the present invention, not only the plurality of photoelectricconversion elements, but also the TCP and/or the FPC, which is necessaryfor driving the plurality of photoelectric conversion elements, isinstalled on the reverse surface of the information reading surface ofthe first substrate.

Therefore, the TCP and/or FPC is formed on the reverse surface of theinformation reading surface. As a result, the information readingsurface is a flat and smooth surface of the photoelectric conversionelement formation substrate, and the protrusion of the installationportion of the semiconductor integrated circuit (IC), the TCP, and/orthe FPC, for example, which has conventionally existed, is eliminated.

As a result, it is possible to provide a manufacturing method of aphotoelectric conversion apparatus in which the protrusion of theinstallation portion toward the surface of the document is eliminated.

In the manufacturing method of the photoelectric conversion apparatus ofthe present invention, the first substrate is made of glass, and thegrinding of the first substrate is chemical grinding in the step ofprocessing. By using a glass substrate as the first substrate, it ispossible to employ the chemical grinding in processing the reversesurface of the first substrate so as to reduce the thickness of thefirst substrate. In the chemical grinding, the thickness of the glasssubstrate is reduced by chemical erosion caused by soaking the firstsubstrate in the solvent. This makes it possible to statically processthe first substrate. Therefore, damages to products in a course ofprocessing can be reduced, as compared, for example, with a case wherethe physical grinding is carried out.

As a result, it is possible to provide a manufacturing method of aphotoelectric conversion apparatus that is capable of preventing theyield of products from being lowered.

INDUSTRIAL APPLICABILITY

The invention is applicable to, for example, an image sensor of amatrix-type image reading apparatus that is a close-touching-typephotoelectric conversion apparatus capable of reading information ofdocuments, photographs, business cards and the like, owing to such anarrangement that large numbers of photoelectric conversion means (e.g.photodiodes, phototransistors) and switching elements (e.g. thin filmtransistors) are disposed on a substrate in a line or two dimensionallyin lines.

1. A photoelectric conversion apparatus, comprising: a photoelectricconversion element formation substrate having, on a photoelectricconversion element formation surface thereof, a plurality ofphotoelectric conversion elements, the photoelectric conversion elementformation surface being a reverse surface of an information readingsurface; and a supporting substrate bonded by an adhesive material tothe photoelectric conversion element formation substrate so that thesupporting substrate is integrated with the photoelectric conversionelement formation substrate and faces the plurality of photoelectricconversion elements on the photoelectric conversion element formationsubstrate.
 2. The photoelectric conversion apparatus as set forth inclaim 1, wherein: the supporting substrate is thicker than thephotoelectric conversion element formation substrate.
 3. A photoelectricconversion apparatus as set forth in claim 1, further comprising: asemiconductor integrated circuit in a peripheral portion of thephotoelectric conversion element formation surface, the semiconductorintegrated circuit being necessary for driving the plurality ofphotoelectric conversion elements.
 4. A photoelectric conversionapparatus as set forth in claim 2, further comprising: a semiconductorintegrated circuit in a peripheral portion of the photoelectricconversion element formation surface, the semiconductor integratedcircuit being necessary for driving the plurality of photoelectricconversion elements,
 5. A photoelectric conversion apparatus as setforth in claim 1, further comprising: a tape carrier package and/or aflexible printed circuit in a peripheral portion of the photoelectricconversion element formation surface, the tape carrier package and/orthe flexible printed circuit being necessary for driving the pluralityof photoelectric conversion elements.
 6. A photoelectric conversionapparatus as set forth in claim 2, further comprising: a tape carrierpackage and/or a flexible printed circuit in a peripheral portion of thephotoelectric conversion element formation surface, the tape carrierpackage and/or the flexible printed circuit being necessary for drivingthe plurality of photoelectric conversion elements.
 7. The photoelectricconversion apparatus as set forth in claim 1, wherein: the plurality ofphotoelectric conversion elements include a semiconductor layer, thephotoelectric conversion apparatus further comprising: a transparentsection between the photoelectric conversion element formation substrateand the semiconductor layer.
 8. The photoelectric conversion apparatusas set forth in claim 2, wherein: the plurality of photoelectricconversion elements include a semiconductor layer, the photoelectricconversion apparatus further comprising: a transparent section betweenthe photoelectric conversion element formation substrate and thesemiconductor layer.
 9. A photoelectric conversion apparatus as setforth in claim 1, further comprising: an X-ray-to-light conversion film,provided on the information reading surface of the photoelectricconversion element formation substrate, for converting an X-ray intolight.
 10. A photoelectric conversion apparatus as set forth in claim 2,further comprising: an X-ray-to-light conversion film, provided on theinformation reading surface of the photoelectric conversion elementformation substrate, for converting an X-ray into light.
 11. Aphotoelectric conversion apparatus as set forth in claim 1, furthercomprising: a display medium between the photoelectric conversionelement formation substrate and the supporting substrate; and an activeelement on the photoelectric conversion element formation surface, fordriving the display medium.
 12. A photoelectric conversion apparatus asset forth in claim 2, further comprising: a display medium providedbetween the photoelectric conversion element formation substrate and thesupporting substrate; and an active element on the photoelectricconversion element formation surface, for driving the display medium.13. The photoelectric conversion apparatus as set forth in claim 11,wherein: the display medium is liquid crystal.
 14. The photoelectricconversion apparatus as set forth in claim 12, wherein: the displaymedium is liquid crystal.
 15. The photoelectric conversion apparatus asset forth in claim 13, wherein: a display mode of the liquid crystaldoes not require a polarizer.
 16. The photoelectric conversion apparatusas set forth in claim 14, wherein: a display mode of the liquid crystaldoes not require a polarizer.
 17. A photoelectric conversion apparatusas set forth in claim 13, further comprising: a light source provided toone side with respect to the supporting substrate, while thephotoelectric conversion element formation substrate is provided to theother side, the light source being used as a light source forilluminating a photographic object while information is read, and as adisplay-use light source while the information is displayed.
 18. Aphotoelectric conversion apparatus as set forth in claim 14, furthercomprising: a light source provided to one side with respect to thesupporting substrate, while the photoelectric conversion elementformation substrate is provided on the other side, the light sourcebeing used as a light source for illuminating a photographic objectwhile information is read, and as a display-use light source while theinformation is displayed.
 19. The photoelectric conversion apparatus asset forth in claim 11, wherein: the display medium is anelectroluminescence element.
 20. The photoelectric conversion apparatusas set forth in claim 12, wherein: the display medium is anelectroluminescence element.
 21. The photoelectric conversion apparatusas set forth in claim 19, wherein: the electroluminescence element isused as a light source for illuminating a photographic object whileinformation is read, and as a light emitting element while theinformation is displayed.
 22. The photoelectric conversion apparatus asset forth in claim 20, wherein: the electroluminescence element is usedas a light source for illuminating a photographic object whileinformation is read, and as a light emitting element while theinformation is displayed.
 23. A manufacturing method of a photoelectricconversion apparatus for reading information, comprising the steps of:installing, on a reverse surface of an information reading surface of afirst substrate, (a) a plurality of photoelectric conversion elementsand (b) a semiconductor integrated circuit, which is necessary fordriving the plurality of photoelectric conversion elements; bonding asecond substrate by an adhesive material to the first substrate so thatthe second substrate covers the plurality of photoelectric conversionelements on the reverse surface of the information reading surface; andprocessing the information reading surface of the first substrate byetching or grinding so as to reduce a thickness of the first substrate.24. A manufacturing method of a photoelectric conversion apparatus forreading information, comprising the steps of: installing, on a reversesurface of an information reading surface of a first substrate, (a) aplurality of photoelectric conversion elements and (b) a tape carrierpackage and/or a flexible printed circuit, which is necessary fordriving the plurality of photoelectric conversion elements; bonding asecond substrate by an adhesive material to the first substrate so thatthe second substrate covers the plurality of photoelectric conversionelements on the reverse surface of the information reading surface; andprocessing the information reading surface of the first substrate byetching or grinding so as to reduce a thickness of the first substrate.25. The manufacturing method of the photoelectric conversion apparatusas set forth in claim 23, wherein: the first substrate is made of glass;and the grinding of the first substrate is chemical grinding in the stepof processing.
 26. The manufacturing method of the photoelectricconversion apparatus as set forth in claim 24, wherein: the firstsubstrate is made of glass; and the grinding of the first substrate ischemical grinding in the step of processing.